Abstract

In this letter we report measurements of conductance fluctuations in single-crystal samples of Si doped with P and B close to the critical composition of the metal-insulator transition (n(c) approximate to 4 x 10(18) cm(-3)). The measurements show that the noise, which arises from bulk sources, does not diverge as the loffe-Regal limit (k(F)l --> 1) is approached from the metallic side. At room temperature, the magnitude of the noise shows a shallow maximum at around k(F)l approximate to 1.5 and drops sharply as the insulating state is approached.